One police official told Brazil's O Globo newspaper that authorities are investigating whether a recent post on the store's Facebook page could be connected to the crime. The post showed surveillance footage and asked for help catching shoplifters.

Police plan to compare the images to surveillance footage taken at the shop Monday night, chief homicide investigator Rafael Rangel told the newspaper.

The former football player was last seen Monday night, when two suspects entered his vehicle,CNN affiliate TV Record reported.

On Wednesday morning, police said they found parts of a man's body in a river outside the city and were testing the DNA to see whether the remains belong to Santos, TV Record said.

Authorities have interviewed 10 witnesses so far in the case, police said.

According to local media, Santos' wife, Geisa Silva, worked for the police in one of Rio's shantytowns, but as a social worker giving swimming lessons to children, not as a policewoman.

She told investigators she did not know of any threats made against her husband, according to TV Record.

Some of Santos' relatives and neighbors told O Globo that he didn't have any enemies and said they didn't know what could have motivated the attack.